1. Field of the Invention
The invention relates to a tool utilized to remove particulate matter from within perforations and the like in a subterranean well.
2. Description of the Prior Art
During the flow of production into a well bore, or while injecting water, and the like, into formations in the performance of secondary or tertiary recovery operations, perforations in the well bore or the face of the formations may oftentimes become plugged with sand, silt, or other substances, restricting fluid flow between the formation and the well bore. Heretofore, it has frequently been common practice to utilize a valve apparatus adapted to be opened to create a high pressure differential which results in a sudden high velocity flow of the formation fluid through the perforations and into the well bore, thereby carrying sand, silt, and the like, into the tubing for elevation to the top of the well. As a result, the formation and the perforations are washed or cleared, facilitating subsequent well production or the injection of secondary or tertiary recovery fluids into the formation.
Some of the prior art backsurge valving assemblies require drill or workstring rotation to manipulate one or more of the valves. Such mechanically-activated manipulation may be undesirable in deviated holes and/or in wells of extreme depth. Moreover, some valving assemblies heretofore utilized in backsurge systems incorporate a diaphragm or disc-like element as a valve head which is ruptured by pressure or is "cut" to open the valve, thus possibly contributing to foreign particulate matter in the well which also could adversely affect subsequent operation of the valve assembly by becoming positioned or jammed between two moving parts, etc.
The present invention obviates many of the problems associated with the prior art by providing a backsurge well cleaning tool which is activated by pressure, does not require tubing rotation for valve manipulation, and which does not contain rupturable or cuttable disc elements as valve seats.